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What's it like to stare into the roiling mouth of an active
volcano? Pretty darn cool, say scientists who work at
Antarctica's Mount Erebus, home of one of Earth's only long-lived
lava lakes.

But it's what's happening underneath that glowing, molten rock
that is of even greater interest, and new research is offering
intriguing answers to what lies beneath the lake.

For the first time, scientists have gotten a glimpse of the rocky
plumbing inside the volcano. These geological conduits that pipe
molten rock and gas from deep inside the Earth to the
lava lake atop the imposing, 12,500-foot (3,800-meter) peak
can be seen
in a new video.

It's the first time seismic interferometry, an imaging technique
developed in the last few decades, has been used to peer into a
volcano's inner workings, said Julien Chaput, a Ph.D. candidate
at New Mexico Tech, and the scientist who led the research,
published in the April 14 edition of the journal Geophysical
Research Letters.

"It was a crazy afterthought that we'd try this thing and see if
it worked on the volcano," Chaput said. During the 2007 to 2008
Antarctic field season, a research team had set up more than 90
seismic stations around the upper portions of the mountain for a
different experiment, and they decided to try the novel imaging
technique as an added bonus. "It worked quite well, so we got
lucky," Chaput told OurAmazingPlanet. [ Images:
The Majestic Transantarctic Mountains ]

Mountaintop moment

The images revealed that, as many scientists suspected, Mount
Erebus's insides are a honeycomb of interconnected pipes and
magma chambers that twist and turn through the mountain.

"People have always thought there was this really crazy, tilted
conduit system," Chaput said. His research appears to confirm
that. It revealed at least two sets of geological piping directly
below the lava lake, heading in different directions. One is at
an angle of about 15 degrees — almost sideways.

"We managed to highlight that volcanic systems are extremely
complicated," Chaput said. The work identified many shallow
structures inside the mountain that contain pools of magma, but
the
largest magma chamber, which could be more than 3,000 feet
(900 m) across, lies about 4,000 feet (1,200 m) below the summit.

"The deeper you go, the harder it is to see," Chaput said. The
research allowed them to see the upper 9,500 feet (3,000 m) of
the volcano pretty well, "then it gets fuzzy."

Forecasting future

The novel process used in the research offers tantalizing
prospects for monitoring other volcanoes — particularly those
that threaten more than just penguins and a handful of Antarctic
researchers. Chaput said it could be very useful for imaging the
innards of
volcanoes in the Cascades Mountains of the Pacific Northwest.

Seismic interferometry uses a handy, natural tool — essentially
the volcano's own burps — as the ink, and seismic stations as the
paper to make images of the mountain's insides.

Anytime a large enough gas bubble muscles its way through the
volcano's plumbing, it produces a burst of energy. That energy
glances off the rocky walls of the magma piping inside the
volcano. If one wall is at an angle that faces a seismic station,
that station makes a note of where that wall is — a bit like the
way a bat bounces sound waves around to figure out where things
are, Chaput said.

"The nice thing about this is that you can create images like
this any time you get seismic activity of any kind — which is all
the time, with volcanoes," Chaput said.

The volcano does the work for you. Over time, it gradually adds
information to the image, filling in the characteristics of the
lava pathways that meander through the mountain.

The method offers a way to passively — and fairly cheaply — learn
about how magma and gas move around inside a volcano, which is
key to better understanding what particular brand of violence a
volcano may unleash, and when.

"Had they taken an image of
Mount St. Helens, they probably would have known it would
blow up on the side, instead of the top," Chaput said.

"One of the things we need to do if we're going to
forecast eruptions is really understand how volcanoes work,
and why they erupt the way they do," said Clive Oppenheimer, a
volcanologist at England's University of Cambridge, who was not
associated with Chaput's research. "That comes down to
understanding the plumbing system that brings magma from great
depth," Oppenheimer told OurAmazingPlanet.

Both scientists said that, despite its isolation and the
sometimes atrocious conditions, Erebus offers the perfect place
to figure that out. It stays active — but not too active —
allowing scientists to poke and prod a volcano with a beating
heart, yet one that is not likely to bite back. [ World's
Five Most Active Volcanoes ]

"The generic understanding we can get from Erebus, and applied to
volcanoes worldwide, is very important for identifying why
volcanoes erupt the way they do," Oppenheimer said, "and why they
can suddenly switch their behavior from peaceful to violent."

The research was funded by the National Science Foundation's
Office of Polar Programs. Richard Aster and Philip Kyle,
scientists at New Mexico Tech, were integral to its
success.